“Include your source code files as attachments and the problem id or problem name as subject. Within minutes you will get a reply indicating whether your source code solved the problem, and if it didn't, an indication of what was wrong. Your source code can be in C, C++, Java, or Python (version 2.6). Input is read from stdin”.

Baylor University - ACM-ICPC Live Archive - “Here you will find hundreds of problems used in the ACM-ICPC Regionals and World Finals. You can submit your sources in a variety of languages, trying to solve any of the problems available in our database”.

CheckIO - “A game world you can explore using your programming skills”, with Python 3.3 tasks.